1. Field of the Invention
Aspects of this invention relate generally to fuel systems, and more particularly to enhanced fuel systems operating with multi-fuel mixtures.
2. Description of Related Art
The following art defines the present state of this field:
By way of background, efforts over the past several decades abound directed to various means by which the efficiency of internal combustion engines may be improved or the emissions of such engines reduced. Some of these efforts have focused on the actual engine design, and particularly the fuel delivery, injection, and combustion systems and processes, while other efforts have been directed to improvements to the fuels themselves to somehow increase their combustion effect or the efficiency and uniformity with which they burn and hence the power derived therefrom and/or the reduced emissions resulting from a “cleaner” combustion process. The present application is primarily concerned with the former category of improvements to the fuel system itself, there being presented herein a number of new and improved homogenizing fuel systems and system components, the benefits of which will be readily apparent.
As to the prior art, in sum, all known efforts to increase the efficiency of internal combustion engines have to date led to only marginal success at best. Most such “improvements” have resulted in only a slight increase in actual efficiency and/or were achieved using approaches that are technologically or practically not workable, as either involving fuels that are not readily available or safely used or systems and hardware that add tremendous cost and complexity to the engine. As an example, currently much work is being done in the art in connection with homogenous charge compression ignition (“HCCI”). In ideal “laboratory-type” usage, efficiency gains on the order of thirty percent (30%) are being seen in gasoline internal combustion engines using HCCI. However, due to the sensitive nature of this approach to combustion and its requirement of precise temperature and pressure conditions (compression ratios) in the combustion chambers for the automatic combustion reaction to be set off, under actual road testing where an engine is subjected to various loading demands, the HCCI process breaks down, leading not only to little to no efficiency gains but in some cases to engine failures (predetonation).
Other attempts to improve the efficiency and/or reduce emissions of internal combustion engines have included fuel fractioning, additives in the air intake, which thus don't interact with the fuel until they meet in the combustion chamber, and actual fuel additives or formulations introduced into the combustion chamber in some fashion that for a variety of reasons are relatively less effective given the particular system or implementation method.
First, as to the prior art fuel fractioning approach, generally, a number of references teach on-board fractioning, or separating a fuel into light and heavy distillates, for example, or otherwise conditioning a fuel for varied use depending on the demands of the engine, such as at start-up versus idle versus high RPM's, high or low load, or “warmed” operation. U.S. Pat. No. 2,758,579 to Pinotti and U.S. Pat. No. 2,865,345 to Hilton, commonly assigned and dating to the 1950's, teach systems wherein a liquid residual fuel and a liquid distillate fuel are proportionately mixed and delivered through mechanical metering to the engine. In terms of mixing the fuel fractions, Hilton teaches an “orifice mixer 32,” which is generally defined in the art as an “arrangement in which two or more liquids are pumped through an orifice constriction to cause turbulence and consequent mixing action,” while Pinotti teaches passage of the fuel fractions through a proportioning valve 5 and then on to the closed loop injection circulating system where the mixture is maintained “in an agitated or turbulent condition through header 23 against the back pressure of relief valve 25.” Both Pinotti and Hilton further involve residual and/or distillate fuel heaters to adjust through heat the viscosity of one or more of the fuel fractions to facilitate processing of the fuel mixtures, particularly during cold starting.
More recently, U.S. Pat. No. 6,067,969 to Kemmler et al. teaches a fuel supply system for an internal combustion engine with a fuel tank for liquid fuel, from which a fuel supply line leads to a fuel injection device, and an evaporating and condensing device for low-boiling fuel components also connected to the fuel tank. Also provided is an intermediary condensate tank connected downstream from the evaporating and condensing device, from which tank a condensate line leads to a control valve that regulates supply to the injection device. A residual fuel line for the high-boiling fuel produced in the evaporating and condensing device ends in an additional tank, from which a residual fuel supply line runs to a reversing valve mounted in the fuel supply line. The reversing valve is controlled so that the high-boiling fuel is supplied from the residual fuel supply line into the fuel supply line going to an injection device of the engine. Kemmler states that “[u] sing shuttle valve 3 and reversing valve 6, it can be ensured that the engine is supplied with the best possible fuel components for optimum operation by selectively feeding it with fuel, i.e., original fuel, low-boiling fuel from condensate line 15, or high-octane residual fuel from residual fuel line 22.”
Similarly, U.S. Pat. Nos. 6,571,748 and 6,622,664 to Holder et al. teach a fuel fractioning system as part of a fuel supply system for an internal combustion engine having a fuel tank for liquid fuel, a fuel pump that draws fuel from the fuel tank and pressurizes the fuel to an injection pressure at which the fuel is made available to the internal combustion engine, a fuel-fractionating device, which is preferably in the form of an evaporator or evaporation chamber and that produces at least one liquid fuel fraction from the fuel, and an accumulator that receives the liquid fuel fraction from the fuel-fractionating device, stores it, and makes it available to the internal combustion engine, the fuel and fuel fraction being fed to the internal combustion engine by the fuel supply system as a function of demand, with the accumulator being a pressure accumulator and including a pressure-generating means for pressurizing the fuel fraction in the pressure accumulator up to the injection pressure. In a further embodiment, the fuel and the fractions are mixed in a mixing chamber according to a performance graph stored in a control unit depending on the operating state of the engine and the mixture is then supplied to the engine in a controlled manner. Holder states in the '664 patent that “[a]s far as the inventive concept is concerned it is unimportant whether the fuel fractions are present in gaseous or liquid form,” yet it is also stated that “the fuel mixture [is injected] into the individual combustion chambers of the internal combustion engine in the conventional manner,” such that Holder effectively does not teach or enable injection of a liquid-gaseous fuel mixture. Rather, Holder discloses a fuel system that splits a liquid fuel into at least two fractions on board, such as a relatively high and relatively low boiling point fraction as through vacuum evaporation, which fractions are then mixed in a manner or ratio that “is optimal for the momentary engine operating state,” such that a dynamic or continuously variable fuel mix is required in the invention, much like Kemmler in this respect. Holder's primary objective appears to be emissions control.
And even more recently in connection with fuel fractioning systems, U.S. Pat. Nos. 7,028,672 and 7,055,511 to Glenz et al. teach a fuel supply system for an internal combustion engine having two separate storage containers for liquid fuels, both connected to a first controllable valve that is connected, via a connecting line including a fuel pump, to an inlet of a second controllable valve having two outlets in communication by separate fuel lines with a fuel injection nozzle of the internal combustion engine, each of the two separate fuel lines including a fuel pressure regulator, one being in communication with one and the other with the other of the two separate fuel storage containers for returning excess fuel to the fuel storage container from which fuel is being supplied to the fuel injection nozzle. Specifically, the Glenz systems are directed to delivering alternating liquid fuels to one injector of the engine at a time as derived from a fuel fractionation unit and pushed into the injectors as by compressed air or other gas, which is a similar approach to the well-known original Rudolph Diesel injection practice. Like Holder, the focus of Glenz is also emissions reduction, with specific emphasis on the start-up or warm-up phases of engine operation, and particularly on the on-board mixing and controlled use of optimized “starting” and “main” fuel mixtures as produced by the fuel fractionation unit.
Regarding prior art fuel fractioning systems, then, it will be appreciated that there is taught only liquid fuel or fuel fraction co-mixtures that are then introduced to the engine's fuel injection system typically in a controlled, variable manner to adjust to the demands of the engine while still reducing emissions, such as when cold starting and the like, without any teaching or suggestion that a circulation loop and/or volumetric expansion device would exist outside the fuel injection system as part of the overall fuel delivery system of the engine wherein co-mixtures of liquid and gaseous fuels would be sufficiently mixed and maintained in such a substantially homogeneous state of mixture until being delivered to the engine's fuel injection system for better atomization of the fuel mixture upon injection and thus more efficient combustion.
Turning to the introduction of a fuel additive such as propane or hydrogen through the air intake rather than in the fuel stream, there are known in the art a number of approaches whereby such an additive enters the combustion chamber as part of the air flow. For example, U.S. Pat. No. 7,019,626 to Funk teaches systems, methods and apparatuses of converting an engine into a multi-fuel engine in which some of the combusted gasoline or diesel fuel is replaced in the combustion chamber by the presence of a second fuel such as natural gas, propane, or hydrogen introduced through the air intake or separately directly into the combustion chamber. The Funk system includes a control unit for metering the second fuel and a passenger compartment indicator that indicates how much second fuel is being combusted relative to the diesel or gasoline. Funk indicates that the purpose of the invention is to address the emissions shortcomings of diesel engines and states that the various embodiments disclosed reduce particulate emissions while providing “an inexpensive diesel or gasoline engine conversion method and apparatus that informs the operator of the amount of alternative fuel that is being combusted.”
In Korean Patent Application Publication No. KR 2004/015645A, Bai teaches that liquid and gaseous fuels are mixed and then immediately passed into the combustion chamber through the air intake. Specifically, Bai discloses a jet mixer 1 comprising a gas and liquid fuel mixing pipe 15 arranged at the ends of a gas fuel supply pipe 11 and a liquid fuel supply pipe 13 so as to mix the fuels supplied from the supply pipes, wherein the gas and liquid fuel mixing pipe 15 has outlet holes and a fuel filter 17 is spaced from the mixing pipe 15 to filter off large particles from the mixed fuel, which then passes through a mixed fuel supply pipe 19 to the engine.
Clearly, in any such case where a fuel additive is introduced into the combustion chamber by way of the air intake, or even by being injected separately from the primary liquid fuel, more about which is said below in connection with further prior art examples, there is provided no means by which the primary and secondary fuels, or liquid and gaseous fuels, are able to sufficiently mix together prior to the injection and combustion events.
Turning now to the introduction of a fuel additive such as propane or hydrogen in the fuel stream, specifically, U.S. Pat. No. 6,845,608 to Klenk et al. teaches a method for operating an internal combustion engine in which at least two different fuels are simultaneously supplied to at least one combustion chamber of the internal combustion engine. More specifically, Klenk discloses the injection of hydrogen along with diesel fuel through a common injector primarily for the purpose of emissions reduction, just as for most of the “fuel fractioning” prior art discussed above. Similarly, U.S. Pat. No. 6,427,660 to Yang teaches a compression ignition internal combustion engine 7 with at least one combustion chamber 10 having an air inlet 14 and an exhaust outlet 26 with a dual fuel injector being provided having a mixing chamber 46 with an outlet fluidly connected with the combustion chamber 10 via a first valve 54. A liquid fuel line 64 is provided for delivering liquid fuel to the mixing chamber 46. The liquid fuel line 64 is connected to the mixing chamber 46 via a second valve 60. A combustible gas line 56 is provided for delivering compressed combustible gas to the mixing chamber 46. Upon an opening of the first valve 54, the liquid fuel is brought into the combustion chamber 10 by the compressed combustible gas. It is thus clear from such prior art that there is shown only liquid and gaseous fuels essentially being co-injected without any means for sufficiently mixing the additive and the base fuel prior to injection.
Other approaches in the art of bringing together multiple fuels as a common stream even ahead of injection yet involve further disadvantageous features and still without providing a desirable means to substantially homogenously mix particularly liquid and gaseous fuels and maintain such homogeneity prior to injection. For example, U.S. Pat. No. 6,513,505 to Watanabe et al. teaches injectors 2 that are connected to a common rail 4 via respective dispensing conduits 3 and a mixture of a liquid fuel fed from a liquid fuel tank 2 and an additional fluid fed from an additional fluid tank 9 that is then fed to the common rail 4. The additional fluid contained in the mixture is turned to its supercritical state, and the mixture is injected from the injectors 2 to the engine. The inlets of the dispensing conduits 3 are positioned, with respect to the common rail 4, to open out into a liquid fuel layer which will be formed in the common rail 4 when a separation of the mixture occurs. Thus, while teaching that the fuel components, such as diesel or light oil and an additive such as water, carbon dioxide, hydrogen, and hydrocarbon such as alcohol, methane and ethane, can even be mixed upstream of the fuel injection system, here in a choke 12 in line ahead of the injection pump 6, Watanabe further discloses only that the additional fluid be at all times kept in its supercritical state, which is generally defined as being at a temperature and pressure above its thermodynamic critical point, or having characteristics of both a liquid and a gas. To maintain such a supercritical state of the fuel additive, Watanabe teaches maintaining the temperature “lower than the critical temperature Tc of the additional fluid” and the pressure “higher than the vaporizing (liquefying) pressure of the additional fluid” in the fuel line all the way from the additive tank 9 to the pressurizing pump 6. To do so introduces a number of complexities and attendant costs to the Watanabe system. Moreover, maintaining and dealing with these finely balanced physical fuel properties presents further challenges within the injection system, and the common rail 4, specifically. The vertically oriented common rail 4 in Watanabe is expressly configured not only to maintain specific temperatures and pressures but also to allow, as when the engine is off, for separation of the additional fluid, namely the gaseous fuel such as natural gas or methane, from the primary liquid fuel such as diesel, with the diesel occupying the bottom space of the common rail so as to be injected first until the common rail warms up, the additional fluid returns to its supercritical state, and the two fuel components then re-mix to some extent until “finally the two layers in the common rail 4 would disappear.” Therefore, it is clear that Watanabe introduces relatively costly and complex features in its “fuel feeding device” in an effort to maintain the additional fluid in a supercritical or liquid state, which Watanabe indicates is necessary to achieve sufficient mixing with the primary fuel, even expressly teaching that “if the additional fluid vaporizes before it is mixed with the liquid fuel, or before it is turned to its supercritical state even after it is mixed with the liquid fuel, the liquid fuel and the additional fluid cannot mix with each other uniformly.” Watanabe goes on to say that “[i]f the additional fluid vaporizes, the volume thereof increases. Therefore, it is difficult to feed the additional fluid sufficiently.” Thus, Watanabe clearly teaches that the fuel constituents must be kept in a liquid or supercritical state essentially throughout the system while in operation using temperature and pressure in order to adequately mix and later inject the liquid fuel mixture.
Similarly, and in yet another category of prior art multi-fuel systems, there is taught a reverse approach where the gaseous fuel component such as propane becomes the primary combustible fuel and the liquid fuel such as diesel is a secondary ignition or combustion catalyst. For example, International Publication No. WO 2008/141390 to Martin discloses an injection system for a high vapor pressure liquid fuel such as liquefied petroleum gas (i.e., LPG or propane) that “keeps the fuel liquid at all expected operating temperatures” by use of a high pressure pump capable of at least 2.5 MPa pressures. The fuel can be injected directly into the cylinder or into the inlet manifold of an engine via axial or bottom feed injectors and also could be mixed with a low vapor pressure fuel (e.g. diesel) to be injected similarly. The fuel, mixed or unmixed, can be stored in an accumulator under high pressure assisting in keeping the engine running during fuel changeovers and injection after a period of time as in re-starting the engine. The same injectors can be used to inject any of the fuels or mixtures of them. Therefore, like Watanabe and others, Martin also teaches the desirability of maintaining all fuel constituents at all times as liquids to facilitate mixing and other processing of the fuel before and during injection.
In U.S. Patent Application Publication No. US 2008/0022965 to Bysveen et al., there is taught a compression ignition internal combustion engine that operates using a methane-based fuel and again diesel or the like as an “ignition initiator.” The fuel and method of operating the engine can be employed in a range of applications such as, for example, road or marine vehicles or in static applications such as electrical generators. Just as with Watanabe and Miller, Bysveen teaches that the “[g]as fuel is pressurized or liquefied and mixed with [the diesel fuel],” here off-board of the engine or vehicle, and then “[t]he pre-mixed fuel 3 is fed into a storage vessel 4 which maintains the fuel in a pressurized or liquid state.” In an alternative embodiment of Bysveen, “the injector 206 is arranged to receive the two fuel components and to introduce them simultaneously into the combustion chamber.” Here, much like Klenk, for example, “[t]he two components are mixed in the injector immediately before injection into [the] combustion chamber ensuring a uniform dispersion of ignition initiator in the pressurized or liquefied gas.” Accordingly, there is no fuel re-pressurization in Bysveen, Klenk and other such systems, whereby only common rail rather than direct or mechanical injection may be employed, otherwise there may be pump cavitations, and, in the case of Bysveen, additional hardware in the form of specifically-engineered hydraulic injectors is still needed to insure that the liquid-gaseous fuel mixture is adequately injected (that is, that excess vapor formation that could lead to vapor lock is mitigated). Also like Klenk, Holder and others, Bysveen's primary aim is again emissions reduction rather than improved fuel efficiency.
Referring briefly to one further PCT patent application, analogous to Bysveen, International Publication No. WO 2008/036999 to Fisher teaches a dual fuel system and assembly where liquid LPG and diesel are mixed and then distributed via the common rail to the combustion chambers. With the preferred embodiment of the dual fuel system, Fisher asserts that only minor changes are required to the diesel engine without altering the manufacturers' specifications. According to Fisher, the resultant combustion of the liquid fuel mixture provides cleaner emissions and relatively cheaper vehicle operational costs due to essentially the use of a less expensive fuel, not a result of greater efficiency. In a bit more detail, Fisher teaches passive mixing of pre-pressurized liquid diesel and liquid propane in a mixing chamber 28 configured as a spherical reservoir with the respective fuel streams being introduced off-axis one to the other to create a swirling effect and thereby being “adapted to mix a proportioned flow of the liquefied gas and a proportioned flow of diesel to form a liquid fuel mixture.” A wire mesh 61 is placed in the mixing chamber 28 “to facilitate mixing of the fuels” or agitation. Fisher teaches that the liquid fuel mixture is “preferably pumped to a common rail under high pressure so that the liquid fuel mixture remains in a liquid state.” It follows that just as for Watanabe, Bysveen, Miller and others, Fisher also teaches that the liquid and gaseous fuels are to be in liquid state, as by being under sufficient pressure, at all points in the mixing and delivery process within the disclosed dual-fuel system. And as with others, Fisher would appear to again be only concerned with emissions reduction.
Thus, the prior art as summarized above includes various systems by which primarily diesel engines can be converted to operate in a “dual-fuel” or “multi-fuel” mode by fractioning the liquid fuel (Hilton, Pinotti, Kemmler, Holder, and Glenz), by adding another fuel constituent to the fuel stream (Klenk, Yang and Watanabe) or the air intake (Funk and Bai), or by effectively reversing the fuels and injecting a small amount of diesel into the combustion chamber as a catalyst or, in the words of Bysveen, an “ignition initiator,” sometimes known as a “pilot injection,” which ignites or combusts an alternative fuel such as natural gas, propane or hydrogen that was introduced into the combustion chamber through the air intake or directly into the chamber separately from or mixed under pressure with the diesel (Martin, Bysveen and Fisher). Certainly, in any such manner, a percentage of the diesel is replaced by such alternative fuels in the combustion event, resulting in lower exhaust emissions, especially particulate matter. This may also reduce fuel costs if the alternative fuels are cheaper than diesel, though not necessarily reducing overall fuel consumption or actually improving fuel efficiency. Some of the more recent approaches to multi-fuel injection as highlighted above do go so far as to suggest that such alternative fuels be mixed with the diesel fuel at some point upstream, prior to the injection event, but these other references teach that diesel remains a secondary fuel or “ignition initiator” in a small proportion relative to the alternative fuel and/or that specific physical states of the fuel components, such as supercritical or liquefied through sufficiently high pressures, be maintained at all times in order for the fuels to be satisfactorily mixed and co-injected (see Watanabe and also Ishikiriyama and Hibino below), or otherwise provide no teaching or structure for substantially homogenously mixing the fuels prior to injection so as to improve the atomizing effect on the diesel or other primary fuel component of the mixture by the uniform dispersion therethrough of the gaseous, or lower boiling point, fuel component.
Other prior art generally relating to the field of efficiency and/or emissions improvement in internal combustion engines includes the following:
U.S. Pat. No. 4,373,493 to Welsh teaches a method and apparatus for utilizing both a liquid fuel and a gaseous fuel with a minimum change in a standard internal combustion engine. The gaseous and liquid fuels are fed from separate fuel supplies with the flow of fuels being controlled in response to engine load so that at engine idle only gaseous fuel is supplied and combusted by the engine and both gaseous and liquid fuels are supplied and combusted when the engine is operating under load conditions.
U.S. Pat. No. 4,953,516 to van der Weide teaches a device for the intelligent control of a venturi-type carburetor unit for a gaseous fuel, including a pressure regulator, a main throttle valve in the air suction pipe for control of the engine output and a regulating valve in the gas supply pipe between the pressure regulator and the venturi, this valve being coupled to the main throttle valve. By adjusting this mechanical system for providing a too rich air-fuel-mixture under all conditions, only mirror adjustments of the mixture are necessary to provide the engine with the correct mixture required for each load/speed condition. These requirements are stored in a processor, and the latter controls the necessary corrections of the mixture by diluting the gas flow to the main venturi with some air. To this end a small venturi is placed in the gas pipe, the gas flow sucking the diluting air through a mixing air regulating valve, which valve is controlled by the processor in a continuous, analogic intelligent way. Optionally an O2-sensor placed in the exhaust gases may send feed-back signals to the processor.
U.S. Pat. No. 5,207,204 to Kawachi et al. teaches an engine having a combustion chamber and a fuel injection valve for directly injecting a fuel into the combustion chamber. An assist air supplying apparatus supplies assist air to atomize the fuel injected by the fuel injection valve. Assist air supply pressure is controlled so that a given pressure difference is secured between the assist air supply pressure and pressure in the combustion chamber. The assist air, therefore, is supplied under proper pressure for an entire period of fuel injection, to adequately micronize the injected fuel and improve combustion efficiency.
U.S. Pat. No. 5,291,869 to Bennett teaches a fuel supply system for providing liquified petroleum gas (“LPG”) fuel in a liquid state to the intake manifold of an internal combustion engine, including a fuel supply assembly and a fuel injecting mechanism. The fuel supply assembly includes a fuel rail assembly containing both supply and return channels. The fuel injecting mechanism is in fluid communication with the supply and return channels of the fuel rail assembly. Injected LPG is maintained liquid through refrigeration both along the fuel rail assembly and within the fuel injecting mechanism. Return fuel in both the fuel rail assembly and the fuel injecting mechanism is used to effectively cool the supply fuel to a liquid state prior to injection into the intake manifold of the engine.
U.S. Pat. No. 5,816,224 to Welsh et al. teaches a system for storing, handling, and controlling the delivery of a gaseous fuel to internal combustion engine powered devices adapted to run simultaneously on both a liquid fuel and a gaseous fuel. The invention provides a control system having a float controlled solenoid for ensuring that a consistent supply of dry gas is delivered to the engine. The invention uses the sensors and computer of the existing electronic fuel delivery system of the device to adjust the amount of liquid fuel delivery to compensate for the amount of gaseous fuel injection. The invention provides a gaseous fuel control system for a dual fuel device which is integrated and compact, and which preferably includes a fuel fill connection for the gaseous fuel. The invention also provides a horizontal fuel reservoir comprised of end interconnected parallel conduits and, preferably, includes two separate compartments and a pressure relief system for permitting expansion into a relief compartment from a main compartment. It also provides horizontal and vertical interchangeable reservoirs with expansion properties filled by weight.
U.S. Pat. No. 6,213,104 to Ishikiriyama teaches that the state of a liquid fuel such as diesel fuel is made a supercritical state by raising the pressure and the temperature of the fuel above the critical pressure and temperature. Then, the fuel is injected from the fuel injection valve into the combustion chamber of the engine in the supercritical state. When the fuel in the supercritical state is injected into the combustion chamber of the engine, it forms an extremely fine uniform mist in the entire combustion chamber. Therefore, the combustion in the engine is largely improved.
U.S. Pat. No. 6,235,067 to Ahern et al. teaches a scheme for combusting a hydrocarbon fuel to generate and extract enhanced translational energy. In the scheme, hydrocarbon fuel is nanopartitioned into nanometric fuel regions each having a diameter less than about 1,000 angstroms; and either before or after the nanopartitioning, the fuel is introduced into a combustion chamber. In the combustion chamber, a shock wave excitation of at least about 50,000 psi and with an excitation rise time of less than about 100 nanoseconds is applied to the fuel. A fuel partitioned into such nanometric quantum confinement regions enables a quantum mechanical condition in which translational energy modes of the fuel are amplified, whereby the average energy of the translational energy mode levels is higher than it would be for a macro-sized, unpartitioned fuel. Combustion of such a nanopartitioned fuel provides enhanced translational energy extraction by way of, e.g., a reciprocating piston because only the translational energy mode of combustion products appreciably contributes to momentum exchange with the piston. The shock wave excitation provided by the invention, as applied to combustion of any fuel, and preferably to a nanopartitioned fuel, enhances translational energy extraction and exchange during combustion by enhancing translational energy mode amplification in the fuel and by enhancing transfer of an appreciable amount of energy from that translational mode to the piston before the combusted fuel re-equilibrates the translational energy into other energy modes.
U.S. Pat. No. 6,584,780 to Hibino et al. teaches a system that stores densely dissolved methane-base gas and supplies gas of a predetermined composition. A container 10 stores methane-base gas dissolved in hydrocarbon solvent and supplies it to means for adjusting the composition, through which an object of regulated contents is obtained. Preferably, the means for adjusting the composition is means for maintaining the tank in a supercritical state, or piping 48 for extracting substances at a predetermined ratio from the gas phase 12 and liquid phase 16 in the container.
U.S. Pat. No. 6,761,325 to Baker et al. teaches a dual fuel injection valve that separately and independently injects two different fuels into a combustion chamber of an internal combustion engine. A first fuel is delivered to the injection valve at injection pressure and a second fuel is either raised to injection pressure by an intensifier provided within the injection valve, or delivered to the injection valve at injection pressure. Electronically controlled valves control hydraulic pressure in control chambers disposed within the injection valve. The pressure of the hydraulic fluid in these control chambers is employed to independently actuate a hollow outer needle that controls the injection of the first fuel. Disposed within the outer needle is an inner needle that controls the injection of the second fuel. The outer needle closes against a seat associated with the injection valve body and the inner needle closes against a seat associated with the outer needle.
U.S. Patent Application Publication No. US 2007/0169749 to Hoenig et al. teaches a fuel-injection system for injection of fuel into an internal combustion engine that includes at least one fuel injector and a first fuel-distributor line which is connected to the at least one fuel injector. A second fuel-distributor line is provided which is connected to the at least one fuel injector via an individual corresponding lance.
U.S. Patent Application Publication No. US 2008/0029066 to Futonagane et al. teaches a fuel injector (1) in an internal combustion engine, wherein an intermediate chamber control valve (26) operated by the fuel pressure in a common rail (2) is arranged in a fuel flow passage (25) connecting a two-position switching type three-way valve (8) and an intermediate chamber (20) of a booster piston (17). When the fuel pressure in the common rail (2) is in a high pressure side fuel region, the booster piston (17) is operated by this intermediate chamber control valve (26), while when the fuel pressure in the common rail (2) is in a low pressure side fuel region, the operation of the booster piston (17) is stopped by this intermediate chamber control valve (26).
What is still needed and has been heretofore unavailable is a relatively simple and cost-effective engine fuel enhancement system through which efficiency gains on the order of thirty to one hundred percent (30-100%) or more can be achieved. The present invention meets this need and provides further related advantages as described below.